The present invention relates to a special trawl-net for collecting floating products, such as, for example, but not exclusively, hydrocarbon agglomerates resulting from the action of natural elements on a hydrocarbon layer spread over the water surface, or from the treatment of such a layer by the spreading of a binding agent.
It has already been proposed in U.S. Pat. No. 3,653,510 to provide a funnel-shaped collecting device which is towed at the water surface so as to skim floating products which are collected at the trailing or rear end of the device. However, this device is made of an impervious sheet material and thus has a high drag in water.
It has also been proposed in French Pat. No. 2 416 305 to provide a device for collecting materials floating at the water surface, this device comprising two vertical walls made up of nets supported by upright buoyant members, these two walls being respectively connected to tug boats and defining a tapered channel which guides the products to be collected to a gathering portion of the device also composed of netting and located on the rear part or trailing end of the device.
This prior device does not provide in all cases for an efficient channelling of the products towards the gathering rear part, particularly in rough sea.
Moreover, this device comprises a certain number of elements, such as the upright buoyant members which makes it difficult to put the device into operation.
It has been proposed to substitute for this device, a trawl-type netting which comprises, in addition to lateral walls, a ventral or lower face and a dorsal or upper face, for the purpose of better channeling of the products towards the rear part or trailing end where these products are gathered. Such a modification is described in the French Pat. No. 2 227 750.
However, in order to obtain a sufficient efficiency of the latter-discussed trawl net in the contemplated application, it is necessary to make use of a close-mesh netting, which increases the drag or resistance of the trawl to towing.